Earth drilling apparatus

ABSTRACT

A pair of vertically spaced pistons are normally disposed close together in a tall cylinder, with the lower piston rod rigidly connected to a support below the cylinder, and the upper piston rod connected to the upper end of a tube that extends down around the cylinder. The lower end of the tube supports means for holding the upper end of a drill stem and for rotating it. After the apparatus has been fully extended vertically by hydraulic pressure between the pistons, fluid pressure between each piston and the adjacent end of the cylinder first draws the cylinder and tube down around the lower piston and then draws the tube down around the upper piston, whereby the downwardly moving tube causes the stem-supporting means to exert downward pressure on a drill stem continuously.

United States Patent [1 1 Reich et al.

[ 1 EARTH DRILLING APPARATUS [75] Inventors: Wendell L. Reich; Robert C. Paul,

' both of Reno, Nev.

[73] Assignee: Reed Tool Company, Houston, Tex.

[22] Filed: July 25, 1972 [2]] Appl. No.: 275,094

Primary Examiner-Ernest R. Purser Assistant ExaminerWilliam F. Pate, lll

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Peckham June 4, 1974 [57] ABSTRACT A pair of vertically spaced pistons are normally disposed close together in a tall cylinder, with the lower piston rod rigidly connected to a support below the cylinder, and the upper piston rod connected to the upper end of a tube that extends down around the cylinder. The lower end of the tube supports means for holding the upper end of a drill stem and for rotating it. After the apparatus has been fully extended vertically by hydraulic pressure between the pistons, fluid pressure between each piston and the adjacent end of the cylinder first draws the cylinder and tube down around the lower piston and then draws the tube down around the upper piston, whereby the downwardly moving tube causes the stem-supporting means to exert downwardpressure on a drill stem continuously.

5 Claims, 7 Drawing Figures PATENTEDJUN 4 m4 SHEEI 1 Bf 3 EARTH DRILLING APPARATUS One way of drilling shallow wells or other holes in the earth is to hold a vertical drill stem by its upper end while rotating it and pressing downwardly on it continuously by means of rotating mechanism that is moved down a vertical guide member by means of hydraulic pressure. This requires pistons and cylinders which heretofore have been relatively short because if they were made longer they would have to be made so large and heavy as to be impractical. The reason for this is that unless the cylinder and piston rod were large in diameter and heavy, the forces exerted longitudinally on them during drilling would be likely to cause them to bend or buckle. With short piston travel, short drill stems had to be used because the drill driving means had to be raised frequently to permit additional short drill stems to be'connected to those in the ground.

It is among the objects of this invention to provide earth drilling apparatus which is operated by hydraulic pressure, which can accommodate exceptionally long drill stems, which is relatively light in weight and small in size, and yet which remains rigid during operation.

The preferred embodiment of the invention is illustrated in the accompanying drawings, in which FIG. 1 is a side view showing the apparatus extended and ready to drill;

FIG. 2 is a rear view of the upright apparatus retracted;

FIG. 3 is a rear view showing the apparatus partly extended;

FIG. 4 is a rear view showing the apparatus fully extended; FIG. 5 is a fragmentary central vertical section of the lower portion of the extendable members;

FIG. 6 is a similar view of the upper portion of those members; and

FIG. 7 is an enlarged horizontal section taken on the line VII-VII of FIG. 5. 1

Referring to FIG. I of the drawings, a truck 1 is shown on which a long guide member 2 is pivotally mounted on a horizontal axis on a support 3 at the back of the truck, so that during movement of the truck over the road the guide member can be disposed in a reclining position as shown in dotted lines. When the drilling site is reached and jacks 4 have been placed under the truck, the guide member is swung up to upright position behind the truck, as indicated in FIGS. 1 to 4.

The upright guide member includes two vertical columns 6 that are rigidly connected at their top by a cross member 7. Their bottoms are connected by another cross member 8, to which the lower end of a vertical pistonrod 9 is secured. This rod extends about half way up between the two columns of the guide member and supports a piston 10 on its upper end as shown in FIG. 5. The piston rod and piston are disposed in a long vertical cylinder 13 that extends up through an opening in the top cross member 7 of the guide member. The

' lower end of the cylinderis connected to a guide bar 14 sliding in guide member 2. Rigidly mounted in the lower end of the cylinder is a sealing member 15 that slides on the piston rod.

Welded to the inside of the cylinder, preferably mid way of its length, is a ring 16 that may rest on the upper end of the piston rod while the cylinder is in its lowest position, illustrated in FIGS. 2 and 5. Directly above this ring and preferably resting on it is the lower end of an upper piston rod 17 that extends up and out of the top of the cylinder as shown in FIG. 6. This rod is slidably disposed in a sealing member 18 rigidly mounted in the upper end of the cylinder. The lower end of this rod carries a piston 19 slidably engaging the cylinder wall. The projecting upper end of the rod is provided with a transverse opening, through which a pin 21 extends that connects it to the upper end of a tube 22 that extends down around the cylinder nearly to its bottom. This tube is considerably larger in diameter than the cylinder and slides on guide collars 23 and 24 rigidly mounted, respectively, on the upper end of the cylinder and on its central portion around ring 16. As shown in FIG. 2, the lower end of the tube carries slides 26 that slidably engage the columns of the vertical guide memher and connect the tube to them. Secured to these slides and the lower end of the tube is a rearwardly projecting mechanism 27 (FIG. 1) of known construction for connection to the upper end of a drill stem 28 and for rotating the stem. The stem extends down through aligned openings in rearwardly projecting guide plates 29 at the lower end of the guide member, as shown in FIG. 1.

The major portion of the lower piston rod is hollow and contains a pipe 31 (FIGS. 5 and 7) that extends through the upper end of the rod and into ring 16. The lower end of this pipe is connected with a lateral opening 32 in the solid lower end of the rod. The space between the pipe and the wall of the hollow piston rod communicates at its lower end with a second lateral opening 33. Openings 32 and 33 are connected by hoses (not shown) with pumping equipment on the truck. The side wall of the hollow rod is provided with one or more openings 34 a short distance below the lower piston. The side of the lower end of the cylinder has an opening 36 in it connected with the lower end of a conduit, such as a pipe 37, that extends up between the cylinder and the surrounding tube to an opening 38 in the side of the upper end of the cylinder near the Y upper sealing member 18.

OPERATION After the truck has arrived at the location where drilling is to be done and the jacks have been placed and the reclining guide member has been swung up to upright position, hydraulic fluid is pumped through a hose and into opening 32 in the lower end of the lower piston rod. The fluid flows up through pipe 31 and acts upon upper piston 19, which it forces upwardly in the cylinder to thereby raise tube 22 relative to the cylinder. The tube continues to move upwardly around the cylinder until a stop 40 mounted on the upper piston rod a short distance above the upper piston engages the bottom of the upper sealing member 18 in the top of the cylinder. The parts then are in the position shown in F IG. 3.

Continued pumping of fluid into the cylinder now causes the upper piston to lift the cylinder with it, so that the piston and cylinder and encircling tube all move upwardly together as a unit. This continues until a stop 41 mounted on the lower piston rod just below openings 34 is engaged by lower piston 10 and stops further extension of the several elements. They are now in the fully extended position shown in FIGS. 1 and 4.

During elevation or extension of the elements just described, hydraulic fluid that was in the spaces between each piston and the adjacent sealing memberhas to es cape. This occurred by flow down through pipe 37 that connects those two spaces, and through openings 34 and down through the passage between the lower piston and pipe 31 and out through opening 33 connected with the tank of the pumping equipment.

With the apparatus fully extended, a drill stem 28 is put in operating position with its upper end connected to the stem-rotating mechanism 27, which is then set in operation to rotate the stem. The bit on the lower end of the stem must now be pressed down against the ground constantly in order for it to drill a hole or well. This is accomplished by reversing the fluid pressure in the apparatus by switching the pump delivery to opening 33 in the lower end of the lower piston, and connecting opening 32 with the tank. Consequently, fluid is now pumped up through the hollow lower piston rod around pipe 31, and out through openings 34 and into the space in the cylinder between the lower piston and the lower sealing member 15. From here the fluid is forced up through pipe 37 and into the cylinder between the upper piston and sealing member.

It will be seen that the fluid pressure between the lower piston and the lower sealing member now will force that lower sealing member downwardly, thereby drawing the cylinder downwardly around the lower piston. This causes the upper piston rod to pull the tube 22 down also, which applies continuous downward pressure on the drill stem through the medium of the stem-rotating mechanism 27.

When the ring 16 in the center of the cylinder strikes the upper end of the lower piston rod and therefore can go no further down, which is the position shown in F IG.

3, the fluid pressure between the upper piston 19 and sealing member 18 starts to act on the upper piston to cause it to pull the tube down around the cylinder. This continues until the lower end of the upper piston rod engages ring 16, or until the downward movement of the rod or tube is stopped in some other manner. During all of this downward movement or contraction of the apparatus, the fluid in the cylinder between the two pistons is forced down through pipe 31 and out through opening 32 to the tank. v

An important feature of this invention is that while considerable pressure is being exerted downwardly on the drill stem during drilling, the two slender piston rods and the very long cylinder are all under tension. Therefore, they can all have much smaller diameters and the cylinder can have a much thinner wall than would be required if they were under compression. Although the tube 22 is under compression at this time, it has a much greater diameter relative to its length and can therefore withstand the compression forces without buckling. I I

On the other hand, while the apparatus is being extended the piston rods are under compression, but this does not cause them to buckle for two reasons. In the first place, the vertical stress on them is considerably less than during drilling. In the second place, tube 22 and guide collars 23 and 24 and slides 26 stiffen the cylinder, which in turn reinforces the piston rods.

The result of all this is that the apparatus can be made much taller and lighter than otherwise would be the case.

According to the provisions of the patent statutes, we have explained the principle of our invention and have illustrated and described what we now consider to represent its best embodiment. However, we desire to have it understood that, within the scope of the appended claims, the invention, may be practiced otherwise than as specifically illustrated and described.

We claim:

1. Earth drilling apparatus comprising a base, an up-- right guide member connected to the base and extending upwardly therefrom, a vertical fluid pressure cylinder beside said member and movable vertically relative to it, thelower end of the cylinder normally being disposed adjacent the lower end of the upright member, a pair of vertically spaced pistons in the cylinder normally disposed close together, a lower piston rod extending from the lower piston down through the bottom of the cylinder, means rigidly supporting the lower end of said rod, an upper piston rod extending from the upper piston up through the top of the cylinder, annular sealing members mounted in the opposite ends of the cylinder in sliding engagement with the piston rods therein, a tube encircling the cylinder, first means connecting the upper end of the tube to the upper end of the upper piston rod, second means connecting the tube with said upright guide member for vertical movement relative thereto, means for delivering'fluid pressure between the pistons to first move the upper piston upwardly in the cylinder as far as it will go and then move the cylinder upwardly on the lower piston as far as it will go, means supported by the lowerend of said tube beside said upright member for holding the upper end of a drill stem and rotating it, and means for delivering fluid pressure to the raised cylinder between each sealing member and the adjacent piston to pull said tube and drill holding means downwardly.

2. Earth drilling apparatus according to claim 1, in which said tube is spaced radially from said cylinder, said apparatus including vertically spaced spacing collars rigidly mounted on said cylinder in sliding engagement with the inside of said tube.

3. Earth drilling apparatus according to claim 2, in which one of said collars encircles the upper end of said cylinder, and another of said collars is inside the lower end of said tube when the tube is in its upper position on the cylinder.

4. Earth drilling apparatus according to claim 1, in which said upright guide member includes a pair of laterally spaced upright columns, said fluid pressure cylinder is disposed between said columns, and said drill stem holding means projects laterally away from the common upright plane of said columns.

5. Earth drilling apparatus according to claim 1, in which said upright guide member includes a pair of laterally spaced upright columns, said fluid pressure cylinder is disposed between said columns, and said second tube-connecting means include means rigidly connecting the upper ends of the columns and provided with a vertical opening slidingly receiving the upper end of said tube, and means projecting from opposite sides of the lower end of the tube slidable vertically along said columns. 

1. Earth drilling apparatus comprising a base, an upright guide member connected to the base and extending upwardly therefrom, a vertical fluid pressure cylinder beside said member and movable vertically relative to it, the lower end of the cylinder normally being disposed adjacent the lower end of the upright member, a pair of vertically spaced pistons in the cylinder normally disposed close together, a lower piston rod extending From the lower piston down through the bottom of the cylinder, means rigidly supporting the lower end of said rod, an upper piston rod extending from the upper piston up through the top of the cylinder, annular sealing members mounted in the opposite ends of the cylinder in sliding engagement with the piston rods therein, a tube encircling the cylinder, first means connecting the upper end of the tube to the upper end of the upper piston rod, second means connecting the tube with said upright guide member for vertical movement relative thereto, means for delivering fluid pressure between the pistons to first move the upper piston upwardly in the cylinder as far as it will go and then move the cylinder upwardly on the lower piston as far as it will go, means supported by the lower end of said tube beside said upright member for holding the upper end of a drill stem and rotating it, and means for delivering fluid pressure to the raised cylinder between each sealing member and the adjacent piston to pull said tube and drill holding means downwardly.
 2. Earth drilling apparatus according to claim 1, in which said tube is spaced radially from said cylinder, said apparatus including vertically spaced spacing collars rigidly mounted on said cylinder in sliding engagement with the inside of said tube.
 3. Earth drilling apparatus according to claim 2, in which one of said collars encircles the upper end of said cylinder, and another of said collars is inside the lower end of said tube when the tube is in its upper position on the cylinder.
 4. Earth drilling apparatus according to claim 1, in which said upright guide member includes a pair of laterally spaced upright columns, said fluid pressure cylinder is disposed between said columns, and said drill stem holding means projects laterally away from the common upright plane of said columns.
 5. Earth drilling apparatus according to claim 1, in which said upright guide member includes a pair of laterally spaced upright columns, said fluid pressure cylinder is disposed between said columns, and said second tube-connecting means include means rigidly connecting the upper ends of the columns and provided with a vertical opening slidingly receiving the upper end of said tube, and means projecting from opposite sides of the lower end of the tube slidable vertically along said columns. 